ZeroSettle: iMessage Numbers for Businesses and AI Agents
ZeroSettle gives a business or an AI agent its own phone number on iMessage. The number runs on Apple hardware ZeroSettle operates, your code texts customers through a simple API, and replies arrive at your server within a couple of seconds. It also offers a hosted AI agent that answers texts for you and an MCP connector so AI coding tools can set the whole thing up. The company is a Y Combinator Winter 2026 startup founded by two former Apple engineers.
The quick answer: ZeroSettle is a focused, well-documented iMessage-only service with clear rules. It’s good for assistants, support lines and sign-in flows that people text first, and it can start a small number of conversations each day. It doesn’t fall back to SMS outside a limited pilot, and the number belongs to ZeroSettle, not you. A disclosure first: we make Carly, which sells AI phone and texting agents for businesses, and ZeroSettle’s hosted agent does a similar job over iMessage. We’ve kept to what ZeroSettle’s own pages and terms say.
ZeroSettle at a glance
Checked against ZeroSettle’s site, docs, terms and YC profile on November 12, 2026.
| ZeroSettle | |
|---|---|
| What it is | A dedicated iMessage number with a REST API, signed webhooks, an MCP connector and an optional hosted AI agent |
| Founders | Gabe Roeloffs (CEO) and Ryan Elliott (CTO), both former Apple software engineers |
| Company | Y Combinator Winter 2026, San Diego, team of two |
| Plans | Pro ($49/month per number), Growth (from $199/month), Enterprise (custom) |
| Channels | iMessage only; SMS fallback as a limited pilot |
| New conversations | 5 a day per number on Pro, 25+ on Growth; people who text first don’t count |
| Number ownership | Stays with ZeroSettle |
| Best for | Assistants, support lines and sign-in flows that customers text first |
Two products, one name
ZeroSettle started as something else. Its YC profile describes a “drop-in direct billing SDK for mobile apps” that let developers take payments outside the App Store. That product is still around as an app monetization platform with analytics, paywall experiments and web checkout, priced separately. If you land on its general pricing page, you’re looking at that product, not the iMessage API.
The iMessage API is the newer line of business, and the one this page covers. Roeloffs worked on operating systems at Apple, and Elliott was a systems software engineer there. Running iMessage numbers on Apple hardware fits that background, though ZeroSettle is careful to say it “is not affiliated with, endorsed by, or sponsored by Apple Inc.”
How ZeroSettle works
ZeroSettle’s own explainer traces a message’s path. Your server calls the send endpoint with a bearer token. ZeroSettle queues it on your line, which sends one message at a time from Apple hardware in a server facility. Apple’s iMessage network delivers it as a blue bubble. A reply comes back as a signed webhook about one to two seconds after the line receives it.
Its homepage sums up the integration as “a bearer token and three endpoints: send, react, webhook.” There’s no SDK to install: every call is plain HTTPS and JSON. A few details show how carefully the docs are written:
- Timing. A send normally returns in 2 to 5 seconds, and at most about 75 seconds for a text.
- Retries. If your server doesn’t answer within 10 seconds, ZeroSettle retries the webhook after 1, 5 and 20 seconds.
- Signatures. Each webhook is signed with HMAC-SHA256 and rejected if its timestamp is more than 300 seconds off.
- Honest events. “message.sent” means the message left the line. The docs say plainly that no event reports delivered or read.
What customers see is an ordinary iMessage conversation with your brand. ZeroSettle shares your business name and photo with the first message of each conversation. Its homepage notes that “iOS may show ‘Maybe: Your Company’ before a recipient saves your number,” and that the exact display depends on the recipient’s device.
The feature list is broad: photos with captions, voice messages, videos up to 60 seconds, tapbacks, typing indicators in both directions, inline replies, 13 iMessage effects, polls, iOS 26 chat backgrounds, and group chats of up to 31 people. Several numbers can work together behind one API key and webhook.
Sign in with iMessage
One use case is unusual enough to call out. ZeroSettle offers sign-in by text: the user taps a link, Messages opens with a sign-in code already typed, and they hit send. ZeroSettle’s homepage pitches it as “no passwords, no six-digit codes, no email to verify.” For a consumer app where most users are on iPhone, it’s a login that doubles as the start of a conversation.
The hosted AI agent and MCP connector
You don’t have to write a server at all. Switch a number to “Managed by AI Agent,” write a description of your business, and ZeroSettle’s hosted agent, still in beta, answers every inbound text on that number. Each text the agent sends uses one credit, and Pro and Growth come with a starting allowance.
For developers who build with AI tools, ZeroSettle runs an MCP connector. An AI coding agent can sign you up, create your API key, and register and test your webhook. An agent connected to it can also send texts from the line, both to your own phone for testing and to people who asked to hear from you, under the same limits as the API.
Plans and sending limits
| Pro | Growth | Enterprise | |
|---|---|---|---|
| Price | $49/month per number | From $199/month | Custom |
| Best for | Lines people text first | Agents and teams that start conversations | High volume and compliance needs |
| New conversations you start | 5 a day per number | 25+ a day | Cold outreach to “300,000+ new contacts a month” |
| Messages with known contacts | Up to 10,000 a day | Not published | Custom |
| How to buy | Self-serve | Upgrade or book a demo | Through sales |
People who text your number first never count against the new-contact limit, and ongoing conversations aren’t limited. There’s no per-message charge. Numbers can run out: if none are available, you join a waitlist.
The limits explain the product’s shape. Pro is built for an assistant or support line that customers start. Growth is for teams following up with opted-in leads or sending reminders to a list. Only Enterprise is pitched at large-scale outreach.
What ZeroSettle doesn’t do
ZeroSettle is unusually direct about its gaps:
- iMessage only. There’s no RCS or MMS, and SMS fallback exists only as “a limited per-account pilot.” Without it, a first message to someone who isn’t on iMessage fails with an error, so Android users are out of reach.
- No porting or area code choice. ZeroSettle assigns the number, and you can’t bring your own.
- The number isn’t yours. Its iMessage terms say phone numbers “remain the property of ZeroSettle. Once a subscription is no longer active, the number is reclaimed and may be reassigned.” If customers come to know you by that number, plan for that.
- No security certifications claimed. ZeroSettle’s reliability page says it doesn’t claim end-to-end encryption, SOC 2 certification or HIPAA compliance, and its terms warn that content “may not be encrypted.”
Reliability and spam
ZeroSettle’s homepage shows a “99.9% uptime” figure. Its reliability page is clear that this is a statistic, not a service-level agreement, and its terms disclaim uninterrupted operation.
On spam flags, the company says that across more than 10,000 messages a week it has seen a number flagged “only twice.” When it happens, every send fails until ZeroSettle replaces the number at no charge. Your API token, webhook and code stay the same, but recipients see texts from a new number.
Two other points are worth knowing. A STOP message, or a clear request like “take me off your list,” opts that person out across every number on your account, and only START opts them back in. And separately from any flag, iOS 26 can quietly file messages its spam detection judges to be junk into a Spam folder on the recipient’s iPhone. ZeroSettle notes that its “message.sent” event can’t tell you whether that happened.
Terms to know
ZeroSettle’s iMessage terms were last modified on October 22, 2026. Besides number ownership, three clauses stand out:
- Apple risk sits with the customer. ZeroSettle “makes no representation that any use of the Services complies with any Apple agreement, policy, or guideline,” and isn’t responsible for actions Apple takes against a line.
- Consent is required. You need explicit opt-in before messaging anyone, and unsolicited messages are banned.
- Your data can improve ZeroSettle. The terms allow ZeroSettle to “use Customer Data and interactions with its services to develop and improve its systems and offerings.”
Cancellation takes effect at the end of the current billing period, and ZeroSettle can suspend service if your use poses a legal, security or deliverability risk.
How ZeroSettle compares
The managed iMessage providers have each found a different angle:
- ZeroSettle: iMessage only, a hosted AI agent, Sign in with iMessage, and an MCP connector that sets everything up.
- Linq: the infrastructure behind many consumer assistants, with RCS and SMS fallback and managed load balancing.
- Blooio: self-serve lines for small businesses and agencies, plus Apple Messages for Business.
- Photon: open source, and one codebase that also reaches WhatsApp and Telegram.
- Chert: iMessage plus FaceTime audio and video calls for agents.
- messages.dev: a lean developer API with a strict text-first rule.
Who ZeroSettle suits
ZeroSettle fits if:
- Your customers are mostly on iPhone and text you first, for support, concierge requests or an assistant.
- You want sign-in by iMessage in a consumer app.
- You’d like an AI coding tool to set up the integration, or a hosted agent so you don’t need a server.
Look elsewhere if:
- You need to reach Android users. Without the SMS pilot, they’re out of reach.
- You want to keep your number if you ever leave.
- You need SOC 2, HIPAA or an uptime commitment.
And if what you’re after is an AI that answers your business line and texts customers back on any phone, Carly does that out of the box. Add it to ChatGPT or Claude, get a business number, and its agents answer calls, text back missed callers and reply on WhatsApp. It sends standard SMS, which reaches Android and iPhone alike, rather than iMessage. Our missed-call text back and AI text messaging guides show how that works.
FAQ
What is ZeroSettle?
ZeroSettle is a Y Combinator Winter 2026 company that gives businesses and AI agents a dedicated iMessage number, with a REST API, signed webhooks, an MCP connector and an optional hosted AI agent.
Does ZeroSettle work with Android?
Only through a limited SMS fallback pilot that ZeroSettle enables per account. Otherwise, a first message to someone who isn’t on iMessage fails.
Can I keep my ZeroSettle number?
No. ZeroSettle’s terms say numbers remain its property and are reclaimed once a subscription ends. It also doesn’t port in existing numbers.
How many new people can ZeroSettle text per day?
Five new contacts a day per number on Pro and 25 or more on Growth. People who text you first, and ongoing conversations, don’t count.
What is Sign in with iMessage?
A ZeroSettle feature where a user signs in by sending one pre-filled text from Messages, instead of using a password or a one-time code.
Who founded ZeroSettle?
Gabe Roeloffs (CEO) and Ryan Elliott (CTO), who both worked as software engineers at Apple before starting the company in San Diego.
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